This disclosure relates to communications devices and methods.
So-called near-field communications systems, as an example of communications arrangements suitable for propagation via a communications path including at least a part of a human or animal body, do not generally have an antenna of sufficient length to produce an electromagnetic field. They are capable of generating either an electric or magnetic field, but not both and, therefore, the field strength drops off very quickly with distance and there is substantially no free-space propagation.
Because near-field systems do not generate propagating electro-magnetic (EM) fields, near-field systems offer some distinct features that are hard to achieve with traditional radio communications, including privacy, security, location-specific operation (in that a device communicating via this route normally has to be close to the other communicating device, so that at least a relative location can be inferred), low power requirements and implementation simplicity.
Body-coupled communications (BCC), also known as human body communications (HBC), can make use of a near-field system, whereby an electric field propagates over the surface of the human or animal body from one node (transmitter, receiver or both) to another node. BCC offers an additional advantage by allowing the user to signal intent through actions, such as by physically touching an IoT device (Internet of Things, a term used here to refer to a device with embedded electronics to allow it to communicate digitally with another device or server) or another non-networked device (such as a door lock) with which the user would like to interact.